1. Field of the Invention
Embodiments of the present invention relate to electric tools, and in particular to electric tools having a motor housing and a motor received within the motor housing.
2. Description of the Related Art
FIGS. 11 and 12 show a part of a known electric tool having a motor 101 as a power source. As shown in FIG. 11, the motor 101 includes a stator 102 disposed on a radially outer side and fixed within a motor housing 100, and a rotor 103 disposed on a radially inner side within the motor housing 100 and rotatable relative to the stator 102. As shown in FIG. 12, a space defined between the stator 102 and the rotor 103 within the motor housing 100 serves a part of a flow path of cooling air for cooling the motor 101 and extends parallel to a motor axis. A rotary shaft 104, a fan 105 for producing a flow of cooling air, etc., may be assembled with the motor 101 as a motor assembly that is received within the motor housing 100. The motor housing 100 is split into housing halves along a plane including the motor axis. A baffle 106 for regulating the flow of cooling air and ribs for performing various functions may be formed integrally with the inner wall of the motor housing 100. The baffle 106 may serve to regulate the flow of cooling air such that the flow area through the baffle 106 is restricted to the inside of the stator 102. Therefore, a stator coil 107 of the stator 102 that may generate heat during rotation of the motor 101 may be efficiently cooled. This type of known electric tool is disclosed, for example, in Japanese Laid-Open Patent Publication No 2008-290218.
However, in the case of the known electric tool, the motor assembly including the motor 101, etc. is mounted within one of the housing halves of the motor housing 100, which has the baffle 106 integrally molded therewith, from a lateral side with respect to the axial direction. Thereafter, the other of the housing halves is joined to the one of the housing halves to cover the motor assembly, so that the motor assembly may be received within the motor housing 100. For this reason, it is necessary to ensure a space between the baffle 106 and one end of the stator 102 with respect to the axial direction for enabling this mounting operation. In order to set the position of the baffle 106 to be closer to the motor 101, it is necessary to configure the baffle 106 such that the baffle 106 does not interfere with the motor 101 during the mounting operation from the lateral side. In such a case, it may be possible that the function of the baffle 106 for restricting the flow area to the inside of the stator 102 may be degraded, leading to low efficiency of cooling the coil 107. In addition, the baffle 106 is necessary to have a thickness that is enough to enable molding of the baffle 106.
A necessary space for the mounting operation of the motor assembly and a necessary thickness of the baffle may hinder the minimization of the axial length of the entire electric tool.
Therefore, there has been a need in the art for minimizing an axial length of an electric tool without causing degradation in function of a baffle.